1. Field of the Invention
The present invention relates to a retaining ring for use in a fluid pressure cylinder, in which a piston is displaced along an axial direction under the supply of a pressure fluid, and for fixing cover members with respect to a cylinder body in which the piston is installed.
2. Description of the Related Art
Heretofore, a fluid pressure cylinder, having a piston therein displaced under the supply of a pressure fluid, has been used, for example, as a transport device for transporting various workpieces and the like. In such a fluid pressure cylinder, a construction is provided in which a piston is disposed displaceably inside of a cylinder chamber, which is defined at the interior of a tubular cylinder body and is substantially circularly shaped in cross section, and cover members are installed respectively on both ends of the cylinder body, thereby closing the cylinder chamber.
In such a fluid pressure cylinder, for example as disclosed in Japanese Laid-Open Patent Publication No. 10-318213, when cover members are fixed onto the cylinder body, the cover members are affixed through engagement of retaining rings into annular grooves that are formed on an inner circumferential surface of the cylinder chamber, such that the retaining rings project from the inner wall surface thereof. The retaining rings are formed with a roughly C-shaped cross section having an opening therein, and the retaining rings have an elastic force which acts to expand the retaining rings radially outward.
On the other hand, as disclosed in Japanese Laid-Open Patent Publication No. 2003-088937, this type of retaining ring may be provided with a pair of holes at the open ends of the retaining ring. A machine tool is inserted into the holes and the retaining ring is deformed such that the open ends thereof are displaced in directions to mutually approach each other. As a result, the cross sectionally C-shaped retaining ring is deformed so as to be reduced in diameter, and thus, for example, can be installed into an annular groove formed on the inner wall surface of the cylinder chamber.
The fluid pressure cylinder in which the above-mentioned retaining rings are disposed may include a cylinder body equipped with an elliptically shaped cylinder chamber in cross section, with a major axis thereof lying in the horizontal direction. By providing a piston, which also is elliptically shaped in cross section, displaceably inside of the cylinder chamber, a flat shape may be realized that is thin-shaped. In this case, because the cover members also are formed so as to be elliptically shaped in cross section, it may be considered to form the retaining rings with a pair of straight sections corresponding to the cross sectional shape of the cylinder chamber, wherein the straight sections abut against flat surface regions of the cylinder chamber that is formed with the elliptically shaped cross section, and the bent section of the retaining rings is installed so as to abut against an arcuate region of the cylinder chamber.
However, with retaining rings having such straight sections, when holes are provided on end portions of the straight sections, although the straight sections are capable of being deformed by a machine tool that is inserted into the holes, because the holes and the bent section are separated from each other, there is a concern that the amount at which the bent section is deformed may become too small. As a result, deformation of the retaining rings by a desired amount, and installation of the retaining rings with respect to a cylinder chamber having an elliptically shaped cross section, become difficult to perform.
Further, although it might be considered to install the aforementioned cross sectionally C-shaped retaining rings respectively into an arcuate region of the cylinder chamber, whereby an individual cover member is fixed by a pair a retaining rings, because the retaining rings only engage within the arcuate section of the cylinder chamber through an annular groove, there is a concern that the holding force of the cover member by the retaining rings may be lowered.